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Reaumur (Rene Antoine Ferchault de Reaumur (1683-1757), inventor of
the Reaumur thermometer and author of "Memoires pour servir a
l'histoire naturelle des insectes."--Translator's Note.) devoted one
of his papers to the story of the Chalicodoma of the Walls, whom he
calls the Mason-bee. I propose to go on with the story, to complete it
and especially to consider it from a point of view wholly neglected by
that eminent observer. And, first of all, I am tempted to tell how I
made this Bee's acquaintance.

It was when I first began to teach, about 1843. I had left the normal
school at Vaucluse some months before, with my diploma and all the
simple enthusiasm of my eighteen years, and had been sent to
Carpentras, there to manage the primary school attached to the
college. It was a strange school, upon my word, notwithstanding its
pompous title of 'upper'; a sort of huge cellar oozing with the
perpetual damp engendered by a well backing on it in the street
outside. For light there was the open door, when the weather
permitted, and a narrow prison-window, with iron bars and lozenge
panes set in lead. By way of benches there was a plank fastened to the
wall all round the room, while in the middle was a chair bereft of its
straw, a black-board and a stick of chalk.

Morning and evening, at the sound of the bell, there came rushing in
some fifty young imps who, having shown themselves hopeless dunces
with their Cornelius Nepos, had been relegated, in the phrase of the
day, to 'a few good years of French.' Those who had found mensa too
much for them came to me to get a smattering of grammar. Children and
strapping lads were there, mixed up together, at very different
educational stages, but all incorrigibly agreed to play tricks upon
the master, the boy master who was no older than some of them, or even

To the little ones I gave their first lessons in reading; the
intermediate ones I showed how they should hold their pen to write a
few lines of dictation on their knees; to the big ones I revealed the
secrets of fractions and even the mysteries of Euclid. And to keep
this restless crowd in order, to give each mind work in accordance
with its strength, to keep attention aroused and lastly to expel
dullness from the gloomy room, whose walls dripped melancholy even
more than dampness, my one resource was my tongue, my one weapon my
stick of chalk.

For that matter, there was the same contempt in the other classes for
all that was not Latin or Greek. One instance will be enough to show
how things then stood with the teaching of physics, the science which
occupies so large a place to-day. The principal of the college was a
first-rate man, the worthy Abbe X., who, not caring to dispense beans
and bacon himself, had left the commissariat-department to a relative
and had undertaken to teach the boys physics.

Let us attend one of his lessons. The subject is the barometer. The
establishment happens to possess one, an old apparatus, covered with
dust, hanging on the wall beyond the reach of profane hands and
bearing on its face, in large letters, the words stormy, rain, fair.

'The barometer,' says the good abbe, addressing his pupils, whom, in
patriarchal fashion, he calls by their Christian names, 'the barometer
tells us if the weather will be good or bad. You see the words written
on the face--stormy, rain--do you see, Bastien?'

'Yes, I see,' says Bastien, the most mischievous of the lot.

He has been looking through his book and knows more about the
barometer than his teacher does.

'It consists,' the abbe continues, 'of a bent glass tube filled with
mercury, which rises and falls according to the weather. The shorter
leg of this tube is open; the other...the other...well, we'll see.
Here, Bastien, you're the tallest, get up on the chair and just feel
with your finger if the long leg is open or closed. I can't remember
for certain.'

Bastien climbs on the chair, stands as high as he can on tip-toe and
fumbles with his finger at the top of the long column. Then, with a
discreet smile spreading under the silky hairs of his dawning

'Yes,' he says, 'that's it. The long leg is open at the top. There, I
can feel the hole.'

And Bastien, to confirm his mendacious statement, keeps wriggling his
forefinger at the top of the tube, while his fellow-conspirators
suppress their enjoyment as best they can.

'That will do,' says the unconscious abbe. 'You can get down, Bastien.
Take a note of it, boys: the longer leg of the barometer is open; take
a note of it. It's a thing you might forget; I had forgotten it

Thus was physics taught. Things improved, however: a master came and
came to stay, one who knew that the long leg of the barometer is
closed. I myself secured tables on which my pupils were able to write
instead of scribbling on their knees; and, as my class was daily
increasing in numbers, it ended by being divided into two. As soon as
I had an assistant to look after the younger boys, things assumed a
different aspect.

Among the subjects taught, one in particular appealed to both masters
and pupils. This was open-air geometry, practical surveying. The
college had none of the necessary outfit; but, with my fat pay--seven
hundred francs a year, if you please!--I could not hesitate over the
expense. A surveyor's chain and stakes, arrows, level, square and
compass were bought with my money. A microscopic graphometer, not much
larger than the palm of one's hand and costing perhaps five francs,
was provided by the establishment. There was no tripod to it; and I
had one made. In short, my equipment was complete.

And so, when May came, once every week we left the gloomy school-room
for the fields. It was a regular holiday. The boys disputed for the
honour of carrying the stakes, divided into bundles of three; and more
than one shoulder, as we walked through the town, felt the reflected
glory of those erudite rods. I myself--why conceal the fact?--was not
without a certain satisfaction as I piously carried that most delicate
and precious apparatus, the historic five-franc graphometer. The scene
of operations was an untilled, flinty plain, a harmas, as we call it
in the district. (Cf. "The Life of the Fly", by J. Henri Fabre,
translated by Alexander Teixeira de Mattos: chapter 1.--Translator's
Note.) Here, no curtain of green hedges or shrubs prevented me from
keeping an eye upon my staff; here--an indispensable condition--I had
not the irresistible temptation of the unripe apricots to fear for my
scholars. The plain stretched far and wide, covered with nothing but
flowering thyme and rounded pebbles. There was ample scope for every
imaginable polygon; trapezes and triangles could be combined in all
sorts of ways. The inaccessible distances had ample elbow-room; and
there was even an old ruin, once a pigeon-house, that lent its
perpendicular to the graphometer's performances.

Well, from the very first day, my attention was attracted by something
suspicious. If I sent one of the boys to plant a stake, I would see
him stop frequently on his way, bend down, stand up again, look about
and stoop once more, neglecting his straight line and his signals.
Another, who was told to pick up the arrows, would forget the iron pin
and take up a pebble instead; and a third deaf to the measurements of
angles, would crumble a clod of earth between his fingers. Most of
them were caught licking a bit of straw. The polygon came to a full
stop, the diagonals suffered. What could the mystery be?

I enquired; and everything was explained. A born searcher and
observer, the scholar had long known what the master had not yet heard
of, namely, that there was a big black Bee who made clay nests on the
pebbles in the harmas. These nests contained honey; and my surveyors
used to open them and empty the cells with a straw. The honey,
although rather strong-flavoured, was most acceptable. I acquired a
taste for it myself and joined the nest-hunters, putting off the
polygon till later. It was thus that I first saw Reaumur's Mason-bee,
knowing nothing of her history and nothing of her historian.

The magnificent Bee herself, with her dark-violet wings and black-
velvet raiment, her rustic edifices on the sun-blistered pebbles amid
the thyme, her honey, providing a diversion from the severities of the
compass and the square, all made a great impression on my mind; and I
wanted to know more than I had learnt from the schoolboys, which was
just how to rob the cells of their honey with a straw. As it happened,
my bookseller had a gorgeous work on insects for sale. It was called
"Histoire naturelle des animaux articules", by de Castelnau (Francis
Comte de Castelnau de la Porte (1812-1880), the naturalist and
traveller. Castelnau was born in London and died at Melbourne.--
Translator's Note.), E. Blanchard (Emile Blanchard (born 1820), author
of various works on insects, Spiders, etc.--Translator's Note.) and
Lucas (Pierre Hippolyte Lucas (born 1815), author of works on Moths
and Butterflies, Crustaceans, etc.--Translator's Note.), and boasted a
multitude of most attractive illustrations; but the price of it, the
price of it! No matter: was not my splendid income supposed to cover
everything, food for the mind as well as food for the body? Anything
extra that I gave to the one I could save upon the other; a method of
balancing painfully familiar to those who look to science for their
livelihood. The purchase was effected. That day my professional
emoluments were severely strained: I devoted a month's salary to the
acquisition of the book. I had to resort to miracles of economy for
some time to come before making up the enormous deficit.

The book was devoured; there is no other word for it. In it, I learnt
the name of my black Bee; I read for the first time various details of
the habits of insects; I found, surrounded in my eyes with a sort of
halo, the revered names of Reaumur, Huber (Francois Huber (1750-1831),
the Swiss naturalist, author of "Nouvelles observations sur les
abeilles." He early became blind from excessive study and conducted
his scientific work thereafter with the aid of his wife.--Translator's
Note.) and Leon Dufour (Jean Marie Leon Dufour (1780-1865), an army
surgeon who served with distinction in several campaigns, and
subsequently practised as a doctor in the Landes, where he attained
great eminence as a naturalist. Fabre often refers to him as the
Wizard of the Landes. Cf. "The Life of the Spider", by J. Henri Fabre,
translated by Alexander Teixeira de Mattos: chapter 1; and "The Life
of the Fly": chapter 1.--Translator's Note.); and, while I turned over
the pages for the hundredth time, a voice within me seemed to whisper:

'You also shall be of their company!'

Ah, fond illusions, what has come of you? (The present essay is one of
the earliest in the "Souvenirs Entomologiques."--Translator's Note.)

But let us banish these recollections, at once sweet and sad, and
speak of the doings of our black Bee. Chalicodoma, meaning a house of
pebbles, concrete or mortar, would be a most satisfactory title, were
it not that it has an odd sound to any one unfamiliar with Greek. The
name is given to Bees who build their cells with materials similar to
those which we employ for our own dwellings. The work of these insects
is masonry; only it is turned out by a rustic mason more used to hard
clay than to hewn stone. Reaumur, who knew nothing of scientific
classification--a fact which makes many of his papers very difficult
to understand--named the worker after her work and called our builders
in dried clay Mason-bees, which describes them exactly.

We have two of them in our district: the Chalicodoma of the Walls
(Chalicodoma muraria), whose history Reaumur gives us in a masterly
fashion; and the Sicilian Chalicodoma (C. sicula) (For reasons that
will become apparent after the reader has learnt their habits, the
author also speaks of the Mason-bee of the Walls and the Sicilian
Mason-bee as the Mason-bee of the Pebbles and the Mason-bee of the
Sheds respectively. Cf. Chapter 4 footnote.--Translator's Note.), who
is not peculiar to the land of Etna, as her name might suggest, but is
also found in Greece, in Algeria and in the south of France,
particularly in the department of Vaucluse, where she is one of the
commonest Bees to be seen in the month of May. In the first species
the two sexes are so unlike in colouring that a novice, surprised at
observing them come out of the same nest, would at first take them for
strangers to each other. The female is of a splendid velvety black,
with dark-violet wings. In the male, the black velvet is replaced by a
rather bright brick-red fleece. The second species, which is much
smaller, does not show this contrast of colour: the two sexes wear the
same costume, a general mixture of brown, red and grey, while the tips
of the wings, washed with violet on a bronzed ground, recall, but only
faintly, the rich purple of the first species. Both begin their
labours at the same period, in the early part of May.

As Reaumur tells us, the Chalicodoma of the Walls in the northern
provinces selects a wall directly facing the sun and one not covered
with plaster, which might come off and imperil the future of the
cells. She confides her buildings only to solid foundations, such as
bare stones. I find her equally prudent in the south; but, for some
reason which I do not know, she here generally prefers some other base
to the stone of a wall. A rounded pebble, often hardly larger than
one's fist, one of those cobbles with which the waters of the glacial
period covered the terraces of the Rhone Valley, forms the most
popular support. The extreme abundance of these sites might easily
influence the Bee's choice: all our less elevated uplands, all our
arid, thyme-clad grounds are nothing but water-worn stones cemented
with red earth. In the valleys, the Chalicodoma has also the pebbles
of the mountain-streams at her disposal. Near Orange, for instance,
her favourite spots are the alluvia of the Aygues, with their carpets
of smooth pebbles no longer visited by the waters. Lastly, if a cobble
be wanting, the Mason-bee will establish her nest on any sort of
stone, on a mile-stone or a boundary-wall.

The Sicilian Chalicodoma has an even greater variety of choice. Her
most cherished site is the lower surface of the projecting tiles of a
roof. There is not a cottage in the fields, however small, but
shelters her nests under the eaves. Here, each spring, she settles in
populous colonies, whose masonry, handed down from one generation to
the next and enlarged year by year, ends by covering considerable
surfaces. I have seen some of these nests, under the tiles of a shed,
spreading over an area of five or six square yards. When the colony
was hard at work, the busy, buzzing crowd was enough to make one
giddy. The under side of a balcony also pleases the Mason-bee, as does
the embrasure of a disused window, especially if it is closed by a
blind whose slats allow her a free passage. But these are popular
resorts, where hundreds and thousands of workers labour, each for
herself. If she be alone, which happens pretty often, the Sicilian
Mason-bee instals herself in the first little nook handy, provided
that it supplies a solid foundation and warmth. As for the nature of
this foundation, she does not seem to mind. I have seen her build on
the bare stone, on bricks, on the wood of a shutter and even on the
window-panes of a shed. One thing only does not suit her: the plaster
of our houses. She is as prudent as her kinswoman and would fear the
ruin of her cells, if she entrusted them to a support which might
possibly fall.

Lastly, for reasons which I am still unable to explain to my own
satisfaction, the Sicilian Mason-bee often changes the position of her
building entirely, turning her heavy house of clay, which would seem
to require the solid support of a rock, into an aerial dwelling. A
hedge-shrub of any kind whatever--hawthorn, pomegranate, Christ's
thorn--provides her with a foundation, usually as high as a man's
head. The holm-oak and the elm give her a greater altitude. She
chooses in the bushy clump a twig no thicker than a straw; and on this
narrow base she constructs her edifice with the same mortar that she
would employ under a balcony or the ledge of a roof. When finished,
the nest is a ball of earth, bisected by the twig. It is the size of
an apricot when the work of a single insect and of one's fist if
several have collaborated; but this latter case is rare.

Both Bees use the same materials: calcareous clay, mingled with a
little sand and kneaded into a paste with the mason's own saliva. Damp
places, which would facilitate the quarrying and reduce the
expenditure of saliva for mixing the mortar, are scorned by the Mason-
bees, who refuse fresh earth for building even as our own builders
refuse plaster and lime that have long lost their setting-properties.
These materials, when soaked with pure moisture, would not hold
properly. What is wanted is a dry dust, which greedily absorbs the
disgorged saliva and forms with the latter's albuminous elements a
sort of readily-hardening Roman cement, something in short resembling
the cement which we obtain with quicklime and white of egg.

The mortar-quarry which the Sicilian Mason-bee prefers to work is a
frequented highway, whose metal of chalky flints, crushed by the
passing wheels, has become a smooth surface, like a continuous
flagstone. Whether settling on a twig in a hedge or fixing her abode
under the eaves of some rural dwelling, she always goes for her
building-materials to the nearest path or road, without allowing
herself to be distracted from her business by the constant traffic of
people and cattle. You should see the active Bee at work when the road
is dazzling white under the rays of a hot sun. Between the adjoining
farm, which is the building-yard, and the road, in which the mortar is
prepared, we hear the deep hum of the Bees perpetually crossing one
another as they go to and fro. The air seems traversed by incessant
trails of smoke, so straight and rapid is the worker's flight. Those
on the way to the nest carry tiny pellets of mortar, the size of small
shot; those who return at once settle on the driest and hardest spots.
Their whole body aquiver, they scrape with the tips of their mandibles
and rake with their front tarsi to extract atoms of earth and grains
of sand, which, rolled between their teeth, become impregnated with
saliva and form a solid mass. The work is pursued so vigorously that
the worker lets herself be crushed under the feet of the passers-by
rather than abandon her task.

On the other hand, the Mason-bee of the Walls, who seeks solitude, far
from human habitations, rarely shows herself on the beaten paths,
perhaps because these are too far from the places where she builds. So
long as she can find dry earth, rich in small gravel, near the pebble
chosen as the site of her nest, that is all she asks.

The Bee may either build an entirely new nest on a site as yet
unoccupied, or she may use the cells of an old nest, after repairing
them. Let us consider the former case first. After selecting her
pebble, the Mason-bee of the Walls arrives with a little ball of
mortar in her mandibles and lays it in a circular pad on the surface
of the stone. The fore-legs and above all the mandibles, which are the
mason's chief tools, work the material, which is kept plastic by the
salivary fluid as this is gradually disgorged. In order to consolidate
the clay, angular bits of gravel, the size of a lentil, are inserted
separately, but only on the outside, in the as yet soft mass. This is
the foundation of the structure. Fresh layers follow, until the cell
has attained the desired height of two or three centimetres. (Three-
quarters of an inch to one inch.--Translator's Note.)

Man's masonry is formed of stones laid one above the other and
cemented together with lime. The Chalicodoma's work can bear
comparison with ours. To economise labour and mortar, the Bee employs
coarse materials, big pieces of gravel, which to her represent hewn
stones. She chooses them carefully one by one, picks out the hardest
bits, generally with corners which, fitting one into the other, give
mutual support and contribute to the solidity of the whole. Layers of
mortar, sparingly applied, hold them together. The outside of the cell
thus assumes the appearance of a piece of rustic architecture, in
which the stones project with their natural irregularities; but the
inside, which requires a more even surface in order not to hurt the
larva's tender skin, is covered with a coat of pure mortar. This inner
whitewash, however, is put on without any attempt at art, indeed one
might say that it is ladled on in great splashes; and the grub takes
care, after finishing its mess of honey, to make itself a cocoon and
hang the rude walls of its abode with silk. On the other hand, the
Anthophorae and the Halicti, two species of Wild Bees whose grubs
weave no cocoon, delicately glaze the inside of their earthen cells
and give them the gloss of polished ivory.

The structure, whose axis is nearly always vertical and whose orifice
faces upwards so as not to let the honey escape, varies a little in
shape according to the supporting base. When set on a horizontal
surface, it rises like a little oval tower; when fixed against an
upright or slanting surface, it resembles the half of a thimble
divided from top to bottom. In this case, the support itself, the
pebble, completes the outer wall.

When the cell is finished, the Bee at once sets to work to victual it.
The flowers round about, especially those of the yellow broom (Genista
scoparia), which in May deck the pebbly borders of the mountain
streams with gold, supply her with sugary liquid and pollen. She comes
with her crop swollen with honey and her belly yellowed underneath
with pollen dust. She dives head first into the cell; and for a few
moments you see some spasmodic jerks which show that she is disgorging
the honey-syrup. After emptying her crop, she comes out of the cell,
only to go in again at once, but this time backwards. The Bee now
brushes the lower side of her abdomen with her two hind-legs and rids
herself of her load of pollen. Once more she comes out and once more
goes in head first. It is a question of stirring the materials, with
her mandibles for a spoon, and making the whole into a homogeneous
mixture. This mixing-operation is not repeated after every journey: it
takes place only at long intervals, when a considerable quantity of
material has been accumulated.

The victualling is complete when the cell is half full. An egg must
now be laid on the top of the paste and the house must be closed. All
this is done without delay. The cover consists of a lid of pure
mortar, which the Bee builds by degrees, working from the
circumference to the centre. Two days at most appeared to me to be
enough for everything, provided that no bad weather--rain or merely
clouds--came to interrupt the labour. Then a second cell is built,
backing on the first and provisioned in the same manner. A third, a
fourth, and so on follow, each supplied with honey and an egg and
closed before the foundations of the next are laid. Each task begun is
continued until it is quite finished; the Bee never commences a new
cell until the four processes needed for the construction of its
predecessor are completed: the building, the victualling, the laying
of the egg and the closing of the cell.

As the Mason-bee of the Walls always works by herself on the pebble
which she has chosen and even shows herself very jealous of her site
when her neighbours alight upon it, the number of cells set back to
back upon one pebble is not large, usually varying between six and
ten. Do some eight grubs represent the Bee's whole family? Or does she
afterwards go and establish a more numerous progeny on other boulders?
The surface of the same stone is spacious enough to provide a support
for further cells if the number of eggs called for them; the Bee could
build there very comfortably, without hunting for another site,
without leaving the pebble to which she is attached by habit and long
acquaintance. It seems to me therefore, exceedingly probable that the
family is a small one and that it is all installed on the one stone,
at any rate when the Mason-bee is building a new home.

The six to ten cells composing the cluster are certainly a solid
dwelling, with their rustic gravel covering; but the thickness of
their walls and lids, two millimetres (.078 inch--Translator's Note.)
at most, seems hardly sufficient to protect the grubs against the
inclemencies of the weather. Set on its pebble in the open air,
without any sort of shelter, the nest will have to undergo the heat of
summer, which will turn each cell into a stifling furnace, followed by
the autumn rains, which will slowly wear away the stonework, and by
the winter frosts, which will crumble what the rains have respected.
However hard the cement may be, can it possibly resist all these
agents of destruction? And, even if it does resist, will not the
grubs, sheltered by too thin a wall, have to suffer from excess of
heat in summer and of cold in winter?

Without arguing all this out, the Bee nevertheless acts wisely. When
all the cells are finished, she builds a thick cover over the group,
formed of a material, impermeable to water and a bad conductor of
heat, which acts as a protection at the same time against damp, heat
and cold. This material is the usual mortar, made of earth mixed with
saliva, but on this occasion with no small stones in it. The Bee
applies it pellet by pellet, trowelful by trowelful, to the depth of a
centimetre (.39 inch--Translator's Note.) over the cluster of cells,
which disappear entirely under the clay covering. When this is done,
the nest has the shape of a rough dome, equal in size to half an
orange. One would take it for a round lump of mud which had been
thrown and half crushed against a stone and had then dried where it
was. Nothing outside betrays the contents, no semblance of cells, no
semblance of work. To the inexperienced eye, it is a chance splash of
mud and nothing more.

This outer covering dries as quickly as do our hydraulic cements; and
the nest is now almost as hard as a stone. It takes a knife with a
strong blade to break open the edifice. And I would add, in
conclusion, that, under its final form, the nest in no way recalls the
original work, so much so that one would imagine the cells of the
start, those elegant turrets covered with stucco-work, and the dome of
the finish, looking like a mere lump of mud, to be the product of two
different species. But scrape away the crust of cement and we shall
easily recognize the cells below and their layers of tiny pebbles.

Instead of building a brand-new nest, on a hitherto unoccupied
boulder, the Mason-bee of the Walls is always glad to make use of the
old nests which have lasted through the year without suffering any
damage worth mentioning. The mortar dome has remained very much what
it was at the beginning, thanks to the solidity of the masonry, only
it is perforated with a number of round holes, corresponding with the
chambers, the cells inhabited by past generations of larvae. Dwellings
such as these, which need only a little repair to put them in good
condition, save a great deal of time and trouble; and the Mason-bees
look out for them and do not decide to build new nests except when the
old ones are wanting.

From one and the same dome there issue several inhabitants, brothers
and sisters, ruddy males and black females, all the offspring of the
same Bee. The males lead a careless existence, know nothing of work
and do not return to the clay houses except for a brief moment to woo
the ladies; nor do they reck of the deserted cabin. What they want is
the nectar in the flower-cups, not mortar to mix between their
mandibles. There remain the young mothers, who alone are charged with
the future of the family. To which of them will the inheritance of the
old nest revert? As sisters, they have equal rights to it: so our code
would decide, since the day when it shook itself free of the old
savage right of primogeniture. But the Mason-bees have not yet got
beyond the primitive basis of property, the right of the first

When, therefore, the laying-time is at hand, the Bee takes possession
of the first vacant nest that suits her and settles there; and woe to
any sister or neighbour who shall henceforth dare to contest her
ownership. Hot pursuits and fierce blows will soon put the newcomer to
flight. Of the various cells that yawn like so many wells around the
dome, only one is needed at the moment; but the Bee rightly calculates
that the others will be useful presently for the other eggs; and she
watches them all with jealous vigilance to drive away possible
visitors. Indeed I do not remember ever seeing two Masons working on
the same pebble.

The task is now very simple. The Bee examines the old cell to see what
parts require repairing. She tears off the strips of cocoon hanging
from the walls, removes the fragments of clay that fell from the
ceiling when pierced by the last inhabitant to make her exit, gives a
coat of mortar to the dilapidated parts, mends the opening a little;
and that is all. Next come the storing, the laying of the eggs and the
closing of the chamber. When all the cells, one after the other, are
thus furnished, the outer cover, the mortar dome, receives a few
repairs if it needs them; and the thing is done.

The Sicilian Mason-bee prefers company to a solitary life and
establishes herself in her hundreds, very often in many thousands,
under the tiles of a shed or the edge of a roof. These do not
constitute a true society, with common interests to which all attend,
but a mere gathering, where each works for herself and is not
concerned with the rest, in short, a throng of workers recalling the
swarm of a hive only by their numbers and their eagerness. The mortar
employed is the same as that of the Mason-bee of the Walls, equally
unyielding and waterproof, but thinner and without pebbles. The old
nests are used first. Every free chamber is repaired, stocked and
sealed up. But the old cells are far from sufficient for the
population, which increases rapidly from year to year. Then, on the
surface of the nest, whose chambers are hidden under the old general
mortar covering, new cells are built, as the needs of the laying-time
call for them. They are placed horizontally, or nearly so, side by
side, with no attempt at orderly arrangement. Each architect has
plenty of elbow-room and builds as and where she pleases, on the one
condition that she does not hamper her neighbours' work; otherwise she
can look out for rough handling from the parties interested. The
cells, therefore, accumulate at random in this workyard where there is
no organization. Their shape is that of a thimble divided down the
middle; and their walls are completed either by the adjoining cells or
by the surface of the old nest. Outside, they are rough and display
successive layers of knotted cords corresponding with the different
courses of mortar. Inside, the walls are flat without being smooth;
later on, the grub's cocoon will make up for any lack of polish.

Each cell, as built, is stocked and walled up immediately, as we have
seen with the Mason-bee of the Walls. This work goes on throughout the
best part of May. All the eggs are laid at last; and then the Bees,
without drawing distinctions between what does and what does not
belong to them, set to work in common on a general protection for the
colony. This is a thick coat of mortar, which fills up the gaps and
covers all the cells. In the end, the common nest presents the
appearance of a wide expanse of dry mud, with very irregular
protuberances, thicker in the middle, the original nucleus of the
establishment, thinner at the edges, where as yet there are only newly
built cells, and varying greatly in dimensions according to the number
of workers and therefore to the age of the nest first founded. Some of
these nests are hardly larger than one's hand, while others occupy the
greater part of the projecting edge of a roof and are measured by
square yards.

When working alone, which is not unusual, on the shutter of a disused
window, on a stone, or on a twig in some hedge, the Sicilian
Chalicodoma behaves in just the same way. For instance, should she
settle on a twig, the Bee begins by solidly cementing the base of her
cell to the slight foundation. Next, the building rises, taking the
form of a little upright turret. This first cell, when victualled and
sealed, is followed by another, having as its support, in addition to
the twig, the cells already built. From six to ten chambers are thus
grouped side by side. Lastly, one coat of mortar covers everything,
including the twig itself, which provides a firm mainstay for the


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